My Cammack tree starts with Richard Cammack and Alice Atkinson. They had the following children:
John abt 1829, bap Upton cum Kexby Mary abt 1831, bap Upton cum Kexby Anne abt 1834, ditto George abt 1839, Heapham William abt 1841, Heapham Atkinson 1847, Heapham
and possibly more.
I think that Richard may be the one born 1805 at Saxilby who appears on the 1881 census in Willingham living with his son William. William is 35 so was born abt 1846 - but no reason why one William should not die and the next child be named for him.
Furthermore, looking at his grandchildren's names, there are two Adas, two Alices and three Marys. Alice is Richard's wife..but Ada?